An electric vehicle, also referred to as an electric drive vehicle, is a moving vehicle using one or more electric motors as driving system. Not like petroleum-based transportations which are moved by the energy from burning gasoline, the electric vehicles use electric power as their propulsion. They won't generate waste gas. Noise is also less. During the last few decades, increased concern over the environmental impact of the petroleum-based transportation, along with the spectre of peak oil, has led to renewed interest in an electric transportation. Electric power for electric vehicles can be generated from a wide range of sources, including fossil fuels, nuclear power, and renewable sources such as tidal power, solar power, and wind or any combination of those.
In the past, an electric vehicle consumes huge electric power due to their power system. The electric power can only be transmitted to the car through overhead lines. This infrastructure makes the electric vehicles impossible to be popular. Only some of public transportations have access to it. Routes of the public transportation are strictly limited by the lined arrangement. With the development in power systems of electric vehicles, especially in batteries, the electric vehicles become a future star and more and more sources are devoted in this field.
No matter what appearance (bus, truck or motorcycle) the electric vehicle is, the batteries or battery set plays a key part in the car. Charging time becomes shorter from tens of hours to several hours. Battery capacity also glows up very fast. The car can keep running for hours with more than 100 miles and need no charge. Size of batteries also reduces significantly. Obviously, smaller size makes the battery to be separately portable. People who drive the car can easily find some charging station for charging or replace a full charged battery in their house. The only concern is lifetime of the battery. Besides, a method or device to detect batteries to be charged is required.
Some existing inventions have shown devices or methods for detecting and displaying battery information. A prior art is disclosed in FIG. 1. It is capable of displaying the absolute residual ratio of a rechargeable battery associated with the state of degradation, the memory effect, and relative residual ratio of residual amounts to actual amounts for observing individual use environments. It further provides a battery state displaying device for electric vehicles, which can, according to the memory effect, display the states of battery charging, battery life, battery replacement, etc.
A battery state display device 101 for electric vehicles for displaying the states, such as residual capacity, of a rechargeable battery 100, comprises: a display means 102 for displaying the battery states; an absolute residual ratio algorithm means 103 for obtaining the ratio of the residual amount to the initial amount of the rechargeable battery (absolute residual ratio); a relative residual ratio algorithm means 104 for obtaining the ratio of the residual amount to the actual amount of the rechargeable battery 100 (relative residual ratio); a charging ratio algorithm means 105 for obtaining the ratio of the capacity of the chargeable battery during charging to the initial capacity or actual capacity; and a display control means 106 for switching any one of the absolute residual ratio, relative residual ratio, and charging rate thus obtained to the display means 102 for display.
Although the prior art discloses a device for showing battery information, it can not meet the requirements mentioned above. First, it is equipped in an electric vehicle or battery to display battery information. However, a device, placed outside of the electric vehicle or battery, to detect battery is needed. Second, the prior art can not display cycle count of the rechargeable battery. The cycle count relates to lifetime of the battery. When it comes close to the designed cycle count, the battery should be replaced in case any problem happens to the battery.
Therefore, a display device for showing information of a rechargeable battery of an electric vehicle and a charging module using the display device is desirable to complete the electric vehicle charging system.